Alternately heatable and coolable moulding block

Abstract

An alternately heatable and coolable moulding block for manufacturing plate-shaped information carriers from thermoplastic material, which block is composed of a plate of an electrically insulating material which has a thin metal mould containing the information and in which plate a duct for a cooling liquid is provided and of an electrical conductor wound to form a flat induction coil. Between the mould and the insulating plate, there are provided a layer of a material of good thermal conductivity, which layer is in contact with the mould, and a layer of a ferromagnetic material.

What is claimed is: 
     
       1. An alternately heatable and coolable moulding block for manufacturing a plate-shaped information carrier from thermoplastic material, the block comprising a plate of an electrically insulating material which carries a metal mould containing the information and in which plate a duct for a cooling liquid is provided, and an electrical conductor wound to form a flat induction coil, charactrerized in that between the mould and the insulating plate there are provided a layer of a material of good thermal conductivity, which layer is in contact with the mould, and a layer of an electrically conductive ferromagnetic material. 
     
     
       2. A moulding block as claimed in claim 1, characterized in that the electrical conductor is constituted by the wall of the cooling duct. 
     
     
       3. A moulding block as claimed in claim 1, characterized in that the layer of ferromagnetic material has a thickness of 100 μm and the thermally conductive layer has a thickness of 500 μm. 
     
     
       4. A moulding block as claimed in claim 1, 2 or 3, characterized in that the thermally conductive layer is made of copper.